Petrol engines aircooled Refitting cylinder heads

From VW T25(T3)-Tech
Jump to navigationJump to search
katykoo: Hi, Have replaced a second hand cylinder head to my 82 2.0l Aircooled. There are no compressions...

My mate says its because the gaskets weren't replaced when putting the head back on... discovered from JK that I do not need the large cylinder rings, as they were there to help if engines were to be run on low grade fuel... so JK say just put the cylinder head straight onto the block, and the only gaskets are exhaust and rocker please!

Would the gaskets really affect compression and mean that the two cylinders show no compression?

Laurie: It might be a good idea to ask your mechanic HOW he has set the tappets.

1: Has it got the original hydraulic tappets?

2: Has he located the push rods centrally in the hydraulic tappet?

3: Has he understood the difference between sprung and unsprung movement?


1: If he has adjusted solid tappets to hydraulic spec. The valves are open.

2: If he hasn't located the push rods and done the above, the valves are open.

3: If he has adjusted all the free play out of the tappet and then given it the 1.5 to 2 turns, the valves are open.

Chances of having no compression due to not grinding the head in is negligible unless the barrel was severely damaged.

The 2 litre heads currently sold often have a second cut in the combustion chamber which eliminates the need for the head seal. Most original heads won't have that cut, and therefore the leaving out of the seal means that the deck height is far too small. So... if the barrel sealing face on the head is raised by about a millimetre you won't need a seal.